Maaden is a partner in an aluminium venture with Rio Tinto Alcan. Canada's Alcan – before it was taken over by Rio Tinto – and Maaden agreed last April to develop what would be one of the world's largest aluminium-making projects at a cost of $7bn. That includes a smelter, an alumina refinery and a power station.

Maaden will offer Saudi institutional and individual investors 462.5 million of stock, equivalent to 50 per cent of its share capital, at 20 riyals each, the Capital Market Authority (CMA) said in a statement. The sale starts July 5 and ends July 14, it said.

The other 50 per cent will be held by the Public Investment Fund, according to a cabinet statement in March. Saudi retail investors will be guaranteed a minimum 25 shares each, the CMA said.

Maaden Chief Executive Officer Abdullah Dabbagh said in February that the company plans to offer 40 per cent of its capital in an IPO and another 10 per cent to two Saudi state pension funds. The share sale, on which JPMorgan Chase was advising, was initially planned for last year.